For a variety of therapeutic applications, several treatment modalities are currently known in the art including electrical stimulation, heat therapy and thermostimulation.
Electrical stimulation involves the application of an electrical current to a single muscle or a group of muscles through one or more stimulation pads that are temporarily attached to the skin. The resulting muscle contraction can produce a variety of effects from strengthening injured muscles and reducing oedema to relieving pain and promoting healing. The pads are usually quite small and typically powered with a battery. This results in the application of a small amount of power and a low treatment depth of the resulting electric field. The shallow depth of the electric field generated by conventional electrical stimulation systems limits performance and patient benefit. Some systems have attempted to address this limitation by applying more current, often from a line or mains supply source. However, the small size of conventional electrical stimulation pads is such that on the application of larger amounts of power, i.e. the use of higher currents, patients often report the experience of pain or discomfort.
Heat therapy involves the application of heat to the body. Heat therapy is very useful as it has a number of effects such as relaxation of muscle spasm and increased blood flow that promotes healing. However, combination therapy, i.e. the synergistic use of other modalities such as massage, ultrasound and/or electrical stimulation has been found to be more effective than heat therapy alone.
Thermostimulation is one such combination therapy that involves the use of heat therapy and electrical stimulation simultaneously. With thermostimulation, the healing benefits of heat are provided along with the strengthening, toning, pain relieving and healing benefits of electrical stimulation. Moreover, the application of heat has been found effective in that it allows the patient to tolerate higher currents. This yields higher electric field strengths, greater depths of penetration and, therefore, more positive results than could be achieved with electrical stimulation without heat. Thermostimulation can be performed using pads that are temporarily attached to the skin.
Conventional pads for thermostimulation are small, hard and die cut with sharp flat edges. The rectangular shape of such pads does not conform to the natural shape of muscle tissue. Moreover, conventional thermostimulation pads are generally inflexible and yield to breakage of the heating element if bent or folded too frequently.
The applicant's earlier patent application, WO 2011/064527, describes a solution to the problems of conventional pads for thermostimulation. WO 2011/064527 describes a thermostimulation pad having two elongate substantially parallel electrodes for electrical stimulation, each preferably moulded from carbon loaded silicone. The electrodes are then over-moulded, to hold the electrodes in position relative to one another, thereby providing a single moulded assembly. A heating element is positioned on the moulded assembly and held in place with a layer of silicone. However, whilst the resulting pad has improved flexibility, the inventors have identified a need for a thermostimulation pad that is simpler to manufacture.